JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Xiaobin Zhao,Quansheng Wu,Xufeng Zhou,Shanshan Ye,Jianyan Ding
The realization of Eu 3+ reduction and its reduction mechanism have become focal points in the field of WLED phosphor research. In this study, the reduction of Eu 3+ was successfully achieved through cationic substitution strategy by replacing Zr 4+ with Hf 4+ in Na 2 ZrSiO 5 :Eu 3+ . The effects of substituting Hf 4+ for Zr 4+ on the phase, crystal structure, and luminescence properties of Na 2 Zr 1- x Hf x SiO 5 :Eu 0.03 (0 ≤ x ≤ 1) were thoroughly investigated based on Rietveld refinement , spectral data, DFT calculation and electronegativity of ions. Comprehensive consideration was given to the effect of site size change and site reducibility on Eu 3+ reduction. The results demonstrate that the reduction of Eu 3+ in Na 2 Zr 1- x Hf x SiO 5 :Eu 0.03 is attributed to the alteration in inducible effect caused by cationic substitution and the enhancement in site reducibility rather than changes in site size. Therefore, the cationic substitution strategy based on induction effect presents a novel approach for achieving Eu 3+ reduction and offers a new insight into developing and modifying Eu 2+ -activated phosphors.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2021
·
IF 3.599
Yanzhen Yin,Maochen Zhu,Yue Zhang,Chen Hu,Zhen Wang,Yang Che,Jingyao Lu,Ruyi Sun,Jiaqi Zhao,Bing Teng,Jianhong Li,Shijia Sun,Degao Zhong
High quantum efficiency and thermal stability have always been the goals to pursue and challenges for lighting application. In this work, sunlight-like white emission has been achieved in a new prepared single phased Rb 2 CaP 2 O 7 : 0.005Ce 3+ , 0.01Eu 2+ phosphor, which exhibits high internal quantum efficiency (IQE = 74.36%), external (EQE = 56.77%) quantum efficiency and excellent thermal stability. Based on the broadband emission from 4f-5d transitions of Ce 3+ /Eu 2+ ions and high energy transfer efficiency of Ce 3+ →Eu 2+ (measured up to 60%), the extremely wide color-tunable emission from blue-violet to white and then to orange-yellow is realized in Rb 2 CaP 2 O 7 : 0.005Ce 3+ , xEu 2+ phosphors. Moreover, a prototype WLED device is packaged by combing the prepared Ra 2 CaP 2 O 7 : 0.005Ce 3+ , 0.01Eu 2+ white phosphors with an UV LED chip (λ = 310 nm), and the obtained WLED emits bright sunlight-like white light with color coordinates of (0.377, 0.324). The correlated color temperature (CCT) and the color rendering index (CRI) value of the WLED are 3208 K and 88.4, respectively. These results can provide effective guidance for the design of color-tunable single-phase white phosphors with high luminous efficacy and thermal stability.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Shijie Qiu,Hengwei Wei,Xiaoming Wang,Shuai Zhang,Mengmeng Wang,Yiying Wang,Ling Xu,Huan Jiao
A series of efficient red phosphors, K 2 SiF 6 :Mn 4+ (KSFM) particles with highly regular, uniform and anisotropic shapes, were successfully prepared by a two-step chemical co-precipitation method at room temperature without using surfactant and template. A morphological map for KSFM particles with five distinctive shapes was depicted by adjusting KF-HF precipitator dropping speed. Moreover, the photoluminescence , decay curves and Raman spectral dependence of the KSFM phosphors with different morphologies were investigated. Luminescence intensity of the KSFM phosphors is highly correlated with the morphology of KSFM particles, which gradually increased as the particle shapes changed from cube to octahedron . Whereas, Raman spectra and flame atomic absorption spectrophotometer results indicated that Mn 4+ concentration in a series of KSFM particles decreased gradually. Growth mechanism of particle is discussed base on reticular density and surface energy. White LED devices made of a blue GaN chip merged with yellow phosphor (YAG: Ce 3+ ) and the obtained KSFM red phosphor could produce warm white light. Drive current testing of the fabricated w-LEDs proved the KSFM phosphor in octahedron shape is more stable than that of the KSFM in cubic shape.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Xiaoqian Dong,Zhibin Chen,Lehui Liu,Feifei Yuan,Yisheng Huang,Lizhen Zhang,Zhoubin Lin
Broadband near-infrared (NIR) phosphors play a crucial role in the development of next-generation smart NIR light sources based on blue light-emitting diodes (LEDs). The emission bandwidth is an important parameter for evaluating the performance of these phosphors. Herein, an ultra-broadband NIR phosphor CaMgSi 2 O 6 :Cr 3+ (CMSO:Cr), with a tunable emission band and a full width at half maximum (FWHM) ranging from 138 nm to 393 nm, is obtained by adjusting the doping concentration of Cr 3+ . In the low-concentration doped sample, a single emission peak at 785 nm is observed. When the concentration of Cr 3+ exceeds 1.0 at%, emissions at both 785 nm and 980 nm are detected. The emission peak at 785 nm originates from the [MgO 6 ](Ⅰ) octahedron within the CMSO structure. On the other hand, the emission peak at 980 nm is attributed to the presence of a twisted octahedron [MgO 6 ](Ⅱ), which is caused by defects and vacancies resulting from the charge imbalance when Mg 2+ ions are replaced by Cr 3+ ions. The Cr 3+ ion primarily occupies the [MgO6](Ⅰ) site in the lower-concentration doped sample, which explains the photoluminescence peak at 785 nm. With the increase in the concentration of Cr 3+ ions, more and more Cr 3+ ions preferentially occupy the [MgO 6 ](Ⅱ) octahedral sites, leading to the broad emission at 980 nm. A novel NIR phosphor light source was fabricated by combining a blue chip with CMSO:Cr phosphor. Driven by a current of 60 mA, the NIR light output power of 5.89 mW and 0.76 mW is achieved by using CMSO:0.015Cr and CMSO:0.04Cr, respectively. This work demonstrates that new luminescent centers can be generated by substituting heterovalent ions, resulting in broadened emission spectra.
研究领域:
材料科学
·
光电
·
光子学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2023
·Vol. 12
·期 11
·2302380
·
IF 9
Xiangyi Dai,Xikun Zou,Haoran Zhang,Weibin Chen,Chaowei Yang,Maxim S. Molokeev,Zhiguo Xia,Yingliang Liu,Xuejie Zhang,Mingtao Zheng,Bingfu Lei
Cr 3+ -doped phosphors are highly recognized in various fields for their remarkable luminous efficiency and spectral flexibility, including modern agriculture and horticulture. However, the shortage of suitable Cr 3+ -doped phosphors for far-red LED devices has inhibited their popularization in plant lighting. Herein, an innovative Cr 3+ -doped phosphor Ca 2 YAl 3 Ge 2 O 12 :Cr 3+ (CYAG:Cr 3+ ), achieving a broad far-red emission at 770 nm upon 450 nm blue light excitation is designed. The optimal CYAG:Cr 3+ phosphor exhibits a high internal quantum yield of 78.2% and low thermal-quenching behavior of 85%@373 K. Thus, the fabricated phosphor-converted LEDs (pc-LEDs) for plant far-red lighting have a high output power of 33.3 mW and photovoltaic conversion efficiency of 11.5% at 100 mA. The potential of CYAG:Cr 3+ in plant lighting is assessed by supplementing the far-red lighting of Italian lettuce with fabricated pc-LEDs, and the biomass of Italian lettuce is significantly increased by 33%. The successful development of CYAG:Cr 3+ phosphors provides a high-quality option for plant far-red light devices and further stimulates the development of new Cr 3+ -doped plant-lighting phosphors.
研究领域:
材料科学
·
农业与植物学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2024
·
IF 8
Chaowei Yang,Dongwei Zheng,Xikun Zou,Xiangyi Dai,Baoling Tang,Maxim S. Molokeev,Xuejie Zhang,Haoran Zhang,Yingliang Liu,Bingfu Lei
Far-red (FR) region (beyond 700 nm) lighting sources possess special potential for plant lighting. However, it remains a challenge to obtain high-performance Cr 3+ -doped FR phosphors. This study developed a FR phosphor, Ca 1.8 Mg 1.2 Al 2 Ge 3 O 12 :Cr 3+ (CMAGG: Cr 3+ ), using the cation substitution strategy. Under 438 nm blue light excitation, the phosphors display FR emission centered at 720 nm with a full width at half maximum (FWHM) of 91 nm. Benefit from the favorable match with the FR phytochrome (P fr ), the phosphor is combined with InGaN blue light chips to create a FR phosphor-converted light-emitting diode (pc-LED), which is used in Italian lettuce growth experiments and it results shown in a 15% increase in fresh weight and a 6.5% increase in dry weight. Notably, supplemental FR light modulated its growth morphology. The results of this study will be useful for further research on novel Cr 3+ -doped FR phosphors to meet the precise spectral requirements for plant growth.
研究领域:
植物学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Wei Yan,Xiaohan Yun,Hang Yang,Yi Wei,Guogang Li
Nowadays, non-rare-earth Mn 4+ -activated red phosphors have emerged for improvement of the lighting quality of phosphor-converted white light-emitting-diodes (pc-WLED), owing to the low cost and the admirable luminescence properties. In this work, a novel narrow-band red-emitting Li 3 CsGe 8 O 18 :Mn 4+ phosphor was synthetized based on the component substitution from Li 3 RbGe 8 O 18 , which exhibits the red luminescence centered at 668 nm upon 466 nm excitation. By further designing [Cs + -Rb + ] cation substitution, the photoluminescence intensity and luminescence efficiency are obviously improved. The photoluminescence intensity enhanced 1.75 times than Li 3 RbGe 8 O 18 :Mn 4+ phosphor, while the corresponding internal quantum efficiency (IQE) increased by 1.57 times. According to the Rietveld refinement results, the corresponding mechanism of luminescence enhancement is attributed to the smaller distortion degree of the [Ge(1)O 6 ] octahedron . The pc-WLED device is fabricated by the optimal Li 3 Cs 0.5 Rb 0.5 Ge 8 O 18 :1%Mn 4+ red phosphor, yellow phosphor with Y 3 Al 5 O 12 :Ce 3+ and 460 nm InGaN chip, showing a warm white light emission with low correlated color temperature (4474K) and high color rendering index (90.8). The result implies that the Li 3 Cs 0.5 Rb 0.5 Ge 8 O 18 :1%Mn 4+ phosphor can be used as a potential red phosphor for pc-WLED application.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2025
·Vol. 13
·期 20
·10390-10398
·
IF 5.1
Yi Xu,Xuewan Lin,Jiyou Zhong
Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have emerged as ideal light sources for a variety of advanced spectroscopy applications, demonstrating the importance of developing efficient NIR phosphors. In this work, a Ti4+-containing garnet, Na2CaTi2Ge3O12, was selected as the host material to minimize the ionic size mismatch after Cr3+ substitution. Interestingly, this substitution generates charge self-balance, enabling excellent efficiency of the developed material. Under 465 nm excitation, it exhibits broadband emission covering the first NIR window (λem,max = 790 nm) with a full width at half maximum (FWHM) of 120 nm. The optimized sample achieved a photoluminescence quantum yield (PLQY) of 75%. Moreover, a NIR pc-LED device was fabricated by combining the optimized phosphor with a blue (λem = 455 nm) InGaN chip. Upon application of a driving current of 100 mA, the device demonstrated a NIR output power of 18.24 mW and a corresponding NIR photoelectronic conversion efficiency of 6.49% and exhibited excellent performance in biological tissue imaging and non-destructive testing. Therefore, this work provides an efficient NIR phosphor, which has promising potential in spectroscopy applications.
研究领域:
材料科学
·
光学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Halizati Abulimiti,Aierken Sidike,He Jiuyang
Highly efficient blue-cyan phosphors can fill the cyan gap in conventional white light-emitting diode (LED) devices to improve the spectral continuity while effectively increasing the white LED colour rendering index (Ra). In this study, Ba 0·94 Al 2- x Ga x Si 2 O 8 :0.06Ce 3+ , M + (Li, Na, K, x = 0–0.8) blue-cyan phosphors with a feldspar structure were prepared by a high-temperature solid-phase method using charge compensation and cation substitution strategies. The barium (Ba) vacancy due to the charge-imbalance substitution of Ce 3+ is compensated by the different charge compensators Li + , Na + , and K + . The charge compensators affect the luminescence performance of the samples, with the K + -compensated samples showing the greatest enhancement, with intensities up to 1.8 times that of the uncompensated samples. The cation substitution strategy using Ga 3+ to partially replace Al 3+ further improves the luminescence performance of the Ba 0·94 Al 2 Si 2 O 8 :0.06Ce 3+ , 0.04 K + sample, and the excitation band is also improved. In this case, the luminescence intensity of the Ba 0·94 Al 2 Si 2 O 8 :0.06Ce 3+ luminescent material is increased by a factor of 6, and a broadband blue-cyan phosphor with a full-width at half-maximum of 118 nm containing blue, cyan and green is obtained. The co-doping of charge compensators and partial cation substitution improved the luminescence performance of phosphors. The representative sample Ba 0·94 Al 1.6 Ga 0.4 Si 2 O 8 :0.06Ce 3+ , 0.04 K + has a luminescence intensity at a temperature of 150 °C that is 83.2% of that at room temperature and good thermal stability . The combination of 365 nm near-ultraviolet (NUV) LED chips with Ba 0·94 Al 1.6 Ga 0.4 Si 2 O 8 :0.06Ce 3+ , 0.04 K + and the commercial red powder (Ca, Sr)AlSiN 3 :Eu 2+ yields a white LED device with an Ra of up to 93 and a correlated colour temperature (CCT) of 4825 K. These results show that the blue-cyan phosphor complements the cyan component while simplifying the manufacturing process of white LEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
PHYSICA B-CONDENSED MATTER
·
2025
·
IF 2.8
Qihao Zhou,Zhiyu Qin,Langping Dong,Jingshan Hou,Yongzheng Fang
In this study, a novel green-emitting fluorapatite phosphor Ca 9 Tb(PO 4 ) 5 (SiO 4 )F 2 :Ce 3+ (CTPSF:Ce 3+ ), which features excellent luminous efficiency and thermal stability, was first designed and prepared. High-concentration doping of Tb 3+ enables efficient green emission. Moreover, photoluminescence (PL) spectra and diffuse reflectance spectra reveal that the introduction of Ce 3+ extends the excitation spectrum to the range spanning 200 nm–380 nm, with a significant improvement in efficiency, which stem from the Ce 3+ → Tb 3+ energy transfer process. The introduction of Ce 3+ boosts the photoluminescence intensity of CTPSF by 2.315-fold, delivering a great internal quantum efficiency (IQE) of 73.95 % and an external quantum efficiency (EQE) of 57.86 %. Additionally, the thermal stability improved from retaining 66.3 % of the original intensity at 150 °C to 83.6 % retention of its original intensity at 150 °C. Finally, White-light-emitting diode (WLED) devices were fabricated by employing BaMgAl 10 O 17 :Eu 2+ (blue), CaAlSiN 3 :Eu 2+ (red), and the synthesized CTPSF:Ce 3+ (green) phosphors. Upon applying a forward bias current of 60 mA, the WLED device displayed a high color rendering index (Ra) of 92.7 and a low correlated color temperature (CCT) of 3973 K, validating the potential of this green-emitting phosphor for practical applications in WLED lighting systems.
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2024
·Vol. 26
·期 24
·17182-17190
·
IF 2.9
Zhe-Yong Chen,Xue Ren,Hui-Ling Hu,Meng Liu,Yi Liu,Feng-Lei Jiang
ZnSeTe quantum dots (QDs) attract growing interest owing to their low threats to health and the environment. They are widely applied as emitters in displays and lighting devices. Previous findings have indicated that inorganic halides are excellent candidates for surface ligands on QDs. By incorporating inorganic halides during the synthesis process, the photoluminescence (PL) intensity and quantum yield (QY) of QDs can be significantly enhanced. However, the alteration of surface states in QDs induced by zinc halide modification and the mechanism of formation of trap-state radiative recombination processes have been less discussed. Herein, we proposed a synthesis strategy for ZnSeTe/ZnSe/ZnSeS/ZnS core/shell/shell/shell QDs modified with ZnCl2, and by comparing the morphology and elemental composition of QDs with different amounts of ZnCl2 added, we revealed the regulatory mechanism of nanocrystal growth in the presence of ZnCl2. QDs with modification of ZnCl2 exhibited broad yellow fluorescence, distinct from the intrinsic blue emission. Through spectroscopic and surface ligand analyses, we attributed this yellow emission to the intermediate state energy levels caused by the defects on the surface. Finally, we used the QDs with broad linewidth emission to fabricate a simple white-light-emitting diode (WLED). This work provided new insights into the role of inorganic ligands and the use of a single emitting material in solid-state lighting devices.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nano-Micro Letters
·
2023
·Vol. 16
·期 1
·1-13
·
IF 26.6
Xiao Guang,Li Hao,Yu Zhizhou,Niu Haoting,Yao Yagang
Highly thermally conductive composite films with elimination of graphene nanosheet wrinkles prepared by a constrained drying strategy of in-plane stretching.
Reveals the mechanism of graphene nanosheet wrinkle elimination to improve the thermal conductivity of composite films and demonstrates its use as a heat sink film for cooling flexible LED chips and smartphones.
研究领域:
材料科学
·
热管理技术
·
纳米科技
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）